Spy Who Came in from the Cold, John Le Carre

Started listening and quickly understood that it’s a radionovel, or radiodrama, or whatever it’s called when instead of a book simply read to you, you have different actors, but just the dialogues.
When I switched to a proper audio book I quickly noticed that those that worked on dramatising it, had quite a few liberties with the original book. They added themes, such as the circus theme. In the original book, the Circus is what’s MI6 headquarters is called. But in the drama, Alec is also making a joke about “traveling with a circus and doing a bear act” or something like that, which refers to him spying on the Russians in East Berlin. Or the starting scene, when I spy tries to cross a checkpoint between East and West Berlin. In the drama, there’s a CIA agent that watches it through binoculars and describes everything to Alec. In the book, the CIA agent went to sleep, and Alec even makes a joke about how soft they are.